Caption: Telescope, 17th century artwork. The Latin text at top identifies this section of the book as being about dioptrices, a type of telescope optics. A human eye at upper right is shown looking through the telescope. This artwork is from the 1692 edition of Specimina Philosophiae by the French philosopher and mathematician Rene Descartes (1596-1650). The title translates as 'A Specimen of Philosophy', and the book was first published in 1644. It was a work of natural philosophy, setting forth Descartes' views on the scientific method, optics and meteors.